1. Field of the Invention
The present invention relates to a video game system using terrain profile or topographical information which operates according to game program data stored in a recording medium such as an optical disk, a magnetic disk, a cassette with a built-in semiconductor memory, or the like, and more particularly to a method of representing a distance or height in a display space and a method of displaying a guide in a display space in a video game system using terrain profile information, and a recording medium for use in such a video game system.
2. Description of the Prior Art
Various video game systems which have been proposed in the art include video game systems comprising a combination of a video game machine designed for home use and a television monitor, video game systems designed as video game machines for business use, and video game systems comprising a combination of a personal computer or work station, a display unit, and an audio output unit. These video game systems commonly comprise a controller which can manually be operated by a game player, a recording medium which stores game program data, a central processing unit (CPU) for performing a control process based on the game program data to generate graphic data and audio data, a graphic processor for generating graphic images to be displayed, an audio processor for generating sounds to be outputted, a cathode-ray tube (CRT) for displaying graphic images, and a speaker for outputting sounds. The recording medium may typically be a CD-ROM, a semiconductor memory, a cassette with a built-in semiconductor memory, or the like.
Graphic images generated by the graphic processor and displayed on the CRT will be described below. There are known many different types of video games in the art. However, graphic images generated and displayed in such video games are generally constructed of a controllable image which is variable by commands entered into the controller by the game player and a background image which is either still or variable depending on those commands. Variable background images include background images used to simply give the game player visual changes in the displayed overlay and background images used as a condition for giving the game player an achievement such as a score or the like. One example of the latter background images is a game environment such as a golf course in a golf game.
In a golf game played on a video game system, an image of a golf course and an image of a golfer are displayed in a golf game space on the display screen of a television monitor. When the game player operates the controller of the video game system, the golfer in the golf game space visually moves and swings the golf club to hit the golf ball, which visually flies back into the golf game space. The golfer in the golf game space visually simulates a human golfer as he or she actually plays a golf game on an actual golf course. Therefore, the golf game on the video game system allows the game player to visually simulate playing golf by changing images displayed on the display screen according to commands which are entered into the controller by the game player.
The graphic image of a golf course is related to height data of various areas of the golf course. Based on a command which is entered into the controller by the game player and the height data of the golf course, the CPU calculates a distance which the golf ball is to fly in the golf game space, and then displays the golf ball as traversing the calculated distance. For example, when the golf ball is located in a very low position in the golf game space, if the game player operates the controller to cause the simulated golfer to hit the golf ball weakly toward a very high position in the golf game space, then the golf ball does not move to a position in the golf game space which is intended by the game player. The height data of various areas of the golf course are used in order to give the game player a visual perception as close to actual golf games as possible.
In video games, such as a golf game, where height data are related to various background image areas, it is necessary to display the accurate height of such background image areas so as to allow the game player to operate the controller appropriately. Unless the height of background image areas such as golf course areas is displayed in a certain form, the game player is given no visual basis for operating the controller appropriately.